Rotary gear-pump.



A. SUNDH.

ROTARY GEAR PUMP.

APPLICATION FILED FEB. 1a, 1910.

Patented Mar. 23, 1915.

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A. SUNDH.

ROTARY GEAR PUMP.

APPLIGATION FILED IEB.18, 1910.

Patented Mar. 23, 1915.

2 SHEETS-SHEET 2.

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AUGUST SUNDH, 0F YONKERS, NEW YORK, ASSIG-NOR TO OTIS ELEVATOR COMPANY,OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ROTARY GEAR-PUMP.

Specification of Letters Patent.

Patented Mar. 23, 1915.

Application flied February 18,-1910. Serial No. 544,640.

To all whom it may concern:

Be it known that 1, AUGUST Suunn, a citizen of the United States,residing at Yonkers, in the county of WVestchester and State of NewYork, have invented a new and useful Improvement in Rotary Gear- Pumps,of which the following is a specification.

My invention relates to pumping mechanism and more particularly torotary gear pumps in which intermeshing rotary pump gears are used topump the llquid against pressure.

The invention comprises the use of separate motors or driving elementsfor the pump gears together with means for keeping the motors in exactsynchromsm. It has been found that where intermeshing pump gearshavingrounded gear teeth are driven by separate motors the speed of thegears is irregular and out of synchronism causing considerable leakage,friction and loss of power.

The present invention involves the use of additional gears which act asguiding means to maintain the speeds of the driving shafts exactlyuniform, thereby causing the pump gears to run true, and thus overcomingthe objectionable features incident to the irregular movement of thegears without such guiding means. h I

The exact nature of the invention and the objects sought to be attainedwill appear more fully hereinafter.

In the accompanying drawings which illustrate a construction embodyingthe principles of the present invention, Figure 1 is a part sectionalplan view showing the gear pump and driving motors. .Fig. 2 is asectional elevation view through the pump. Fig. 3 is a part sectionalelevation as indicated by the section line 33 on Fig. 2. Fig. 4: is

a diagrammatic view showing the relation of the intermeshing pump gearstogether with the guiding gears. Fig. 5 is a similar view but with theguiding gears omitted and the pumping gears rotated through a smallangle to indicate an irregular movement when the guiding gears areomitted. Fig. 6 is a view similar to Fig. 4 but with the gears rotatedthrough a small angle.

The rotary gear pump P comprises a supply chamber or casing A mounted onor formed integral with the base B, and a gear casing C located over thesupply chamber. Liquid is admitted to the supply chamber through asupply pipe 10 registering with an opening 11 in the end of the casingA. The pipe 10 is screw-threaded into a cap 12 bolted to the casing. Thesupply pipe 10 may, if desired, be connected with the opposite end ofthe casing A which is provided with an opening 11' covered by a cap 12.WVith this arrangement the cap 12' will be used to cover the opening 11.Within the supply chamber is a screen 13 removably held in guides 14 and15 which may be formed integral with the casing. This screen is for thepurpose of arresting any sand or dirt which may be carried in with thesupply liquid. The screen is inclined as shown so that such foreignsubstances may readily fall to the bottom of the casing. When the supplypipe 10 is connected to the opposite end of the supply chamber, thescreen 13 is placed in the'guides 14', 15'. A horizontal screen 16 isalso employed and may be removably held in position as shown betweenthesupply chamber and pump gear casing. This screen 16 is of finer meshthan the screen 13 and serves to arrest any foreign substances that mayescape through the screen 13, and, being horizontally placed, the dirtreadily falls to the bottom of the casing, and as the screen has a largearea, it is not readily clogged. Those screens are of importance inremoving from the supply liquid all grit or dirt which might otherwisebe carricd by the pump gears to the pressure side of the pump and fromthence downward between the intermeshing gear teeth where it would causecutting and wear of the gears.

The pump gears are separately driven by electric motors M and M whichhave their shafts connected through couplings 1 and 2 respectively withthe gear shafts 3 and 4: on which are keyed the intermeshing rotary pumpgears 5 and 6 located within the cusing C. It will be understood thatany suitable type of electric motor, engine, or other prime mover ordriving element may be employed. The motors are preferably duplicates ordesigned to run at the same speed.

, The teeth on the. umpgears and 6 are nd neo being locked between themas theygnten mesh. These teeth are' preferably substantiallysemi-circular and separated by c o rrespondingly shapedirecesses.

An important feature of the presentin vention resides in the provisionof means i n 'cpmbin'ation with k the separate driving tors" to controlthe relative movement of the drive shafts and cause 'themito rotate atthe same speed. In the present construction I have shown intermeshingspur gears 7 and 8which, as 'well understood by those skilled in-thehrt,will, if properly designed, cause both the shafts'to'rotate at the sameangular velocityand':with out'any slipping or independent movement ofeither shaft. It will be understoodthat any other suitable meanswhiehqwill' accomplish this result is comprehended-in the scope of thepresent invention.

Referring particularly to Figs. l, 5 and 6, the relative movement of thepump gears when properly guided by the spur gears 7 and8, is 'shown'in'Figs. 4 and 6 while Fig.5 indicates an unequal movement of the gears.r'vhen not so guided. In Fig. 4 a broken line -m'zb -connects thecenters f the gear shafts and bisects a tooth c on he pump gear 6, .thisline also bisecting the recess between the adjacent teeth d and e of thegear 5. In Fig. 5 the pump gears have been rotated through a slightangle from the position .showninF-ig. 4. The radial line a of the gear 6as shown intersects the pitch lines f v and gzbelow the point at whichthe radial .lineb of the gear 5 intersects the pitch lines. In otherWords the two radial lines a and b intersect each other at a point tothe left of the pitch lines f and 9 instead of at or between them. Asthe lines a and b are in the same positions relative to the pump gearsas in Fig. 4, it is evident that the gear 6 in Fig.5 has rotated througha greater angle than the gear 5. Inother words the gear 6 has rotatedfaster than the gear 5. As the gears continue to rotate and as the toothe is moving into alinement with the centers of the gears, the gear 5must rotate through a larger angle than the gear 6 in order to bring thegears into a position corresponding to Fig. 4:. This irregular movementWill take place with each pair of intermeshing teeth as the gearsrotate. Such irregular movement of the gears is not a mere theory but isfound to take place in practice and moreover it has been foundpractically impossible to operate the pump gears without such irregularmovement without the use oftsome guiding means such as the gears 7 and 8to insure a uniform movement of the drive shafts. Where such guidingmeans are employed the pump gears rotate at the same velocity, keepingthe gear teeth in their prevent the liqaidgfrom proper relative position.as indicated in Fig. B-b'ythe radlal lines .w'vhich in this caseiategs' t each other at a point equally distan rom h center ofohegearsfIt isittr'benotedkthat the-gears7 and 8 are the power from onemaintain the speeds, of the shafts uniform. The-noise and'wear-and otherobjectionable features incident to the use of such gears,

when used as dri-Vingf gears in connection with 'a'single motor; are notpresent where these gears are used'as inthe present con- Sti'uCtlOnr Thegears?- and 8 maybe in closed in a pas-ing 18' secured-to the pumpcasing by means of rods '19,;and ballbe'ai' ing's20 'or other formo-froller'bearings; are preferably employed for the pumpshafts.Stuffing-boxes 21 are also provided to prevent leakage" from thecasings.

As the oilor other circulating fluid is supplied by the pump gears tothe pump gear chamber under considerable pressure, a portion of thefluid .is carried through the bearingraceways in the partition wall andto the chamber containing the spur gears '7 and 8 and also to the ballbearings in the end walls of the casing. In this way the spur gears?=and '8 and all the bearings are kept well lubricated, and at the sametime the stuffing boxes 21 prevent the escape of .the fluid. from thecasing.

tion of intermeshing pumping gears, shafts on which said gears aresecured, guiding gears for the pumping gears, also secured to saidshafts, anti-friction bearings for said shafts, and communicatingchambers in vwhich said pumping gears, guiding gears and bearings areinclosed.

2. In pumping mechanism, the combination of a casing provided with apartition separating the easing into two compartments, shafts extendinginto the casing,

inter-meshing rotary pump gears located in one' of said compartments andsecured to said shafts, intermeshi-ng spur gears secured to said shaftsand located in the other compartment, anti-friction bearings for saidshafts located in said partition, and a lubricating material circulatedby the pump gears and adapted to maintain said bearings and spur gearslubricated by leakage from the pump gear chamber.

3. In pumping apparatus, the combination of a casing, intermeshing pumpgears Within the casing, shafts on which said gears are mounted,anti-friction bearings name to this specification in the presence ofwithiln 3516b cailing, a lubricating:1 giaterial two subscribingwitnesses. circu ate y t e pump gears, sal earings being lubricated bysaid material, and stuif- AUGUST SUNDH" 5 ing boxes for said shaftslocated in the walls Witnesses:

of the casing outside of said bearings. JOHN F. RULE,

In testimony whereof, I have signed my JAMIE-S G. Bn'rmm.

